(1) Field of the Invention
The present invention relates to a semiconductor memory card for storing digital contents, and a data reading apparatus for reading out the digital contents from the semiconductor memory card. More particularly, the present invention relates to a semiconductor memory card and a data reading apparatus suitable for copyright protection of digital contents.
(2) Description of the Prior Art
The multimedia network technology has developed to the extent that digital contents such as music contents are distributed via a communication network such as the Internet. This makes it possible to access a variety of music or the like provided from around the world at home. For example, a music content can be downloaded into personal computer (hereafter referred to as PC), then stored in a semiconductor memory card loaded into the PC. Also, the semiconductor memory card can be removed from the PC and can be loaded into a portable music player. This enables one to listen to the music while walking. The semiconductor memory cards are compact and lightweight cards containing a nonvolatile semiconductor memory (e.g., a flash memory) and having a large storage capacity.
In such a music distribution, the digital contents to be stored in the semiconductor memory card need to be encrypted beforehand using a key or the like to prevent unauthorized copying of the digital contents. Also, an arrangement is required so that file management software programs, many of which are standard equipment on commercial PCs, cannot copy the digital contents to other storage mediums.
In one possible method for preventing unauthorized copying, only dedicated software programs are allowed to access the semiconductor memory card. For example, when an authentication process between a PC and a semiconductor memory card has completed affirmatively, a PC is allowed to access the semiconductor memory card; and when the authentication process has not completed affirmatively due to the lack of a dedicated software program, the PC is not allowed to access the semiconductor memory card.
However, in the above method in which PCs should always have a dedicated software program to access the semiconductor memory card, free data exchange with users via the semiconductor memory card is not available. As a result, the above method loses a merit of conventional semiconductor memory cards, namely, a merit that file management software programs being standard equipment on commercial PCs can be used to access the semiconductor memory card.
Semiconductor memory cards that can only be accessed through dedicated software programs are superior as storage mediums for storing digital contents since such semiconductor memory cards function to protect copyright of the digital contents. However, the semiconductor memory cards have a problem that they cannot be used as auxiliary storage apparatuses in general-purpose computer systems.